Polyester composition and corresponding article

Abstract

This document describes a polyester composition comprising a semi-aromatic semi-crystalline polyester, a polyolefin, and glass fibers having low D k and low D f ("low D k / D f glass fibers"). The concentrations of the semi-crystalline polyester and the polyolefin are selected such that the polyester weight ratio is from 70% to 95%. Surprisingly, it has been found that when the polyester weight ratio is within the above range, the polyester composition has an excellent balance of dielectric properties (D k and D f ) and mechanical properties (e.g., notched impact strength). It has also been surprisingly found that when the polyester composition further comprises high D k / D f glass fibers, the balance of dielectric and mechanical properties is further improved when the polyester weight ratio is from 75% to 93%. At least in part due to the excellent balance of dielectric and mechanical properties, the polyester composition can desirably be incorporated into components of mobile electronic devices.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 986,837, filed Mar. 9, 2020, and European Patent Application No. 20178769.4, filed Jun. 8, 2020, the entire contents of each of which are incorporated herein by reference for all purposes. Technical Field

[0003] The present invention relates to a polyester composition comprising a semi-aromatic semi-crystalline polyester, a polyolefin, and low D k / D f glass fibers and having an excellent balance of dielectric and mechanical properties. The present invention also relates to articles incorporating these polymer compositions, such as mobile electronic device components. Background Art

[0004] With the rapid spread of 5G communication, there is a continuing need for polymer materials that can desirably be incorporated into applications including mobile electronic device components. More particularly, mobile electronic devices require a good balance of mechanical strength and dielectric properties. With regard to the former, mobile electronic devices are often subjected to drops and impacts and exposed to large temperature variations during use. Therefore, the incorporated polymer material must have good mechanical properties. At the same time, the polymer material must have good dielectric properties (low D k and D f ) such that the material does not undesirably interfere with 5G communication to and from the mobile electronic device. Summary of the Invention

[0005] In one aspect, the present invention relates to a polyester composition comprising: a semi-aromatic semi-crystalline polyester; a polyolefin comprising repeating units (R PO ) including at least 50 mol% of repeating units (R PO ) including at least 4 carbons, preferably at least 5 carbons, the mol% being relative to the total number of repeating units in the polyolefin, the repeating unit (R PO ) being represented by the formula:

[0006]

[0007] wherein R5 to R8 are independently selected from the group consisting of hydrogen and C1-C 10 alkyl. The polyester composition further comprises glass fibers having a D k not greater than 5.5 and a D f not greater than 0.002 as measured at 1 MHz according to ASTM D150, and a polyester weight ratio of from 70% to 95%. The polyester weight ratio is given by the formula: Wherein W PE and W PO are the weights of the semi - aromatic semi - crystalline polyester and the polyolefin in the polyester composition, respectively.

[0008] In some embodiments, the semi - aromatic semi - crystalline polyester is selected from the group consisting of cyclohexylene dimethylene terephthalate (“PCT”), polyethylene terephthalate (“PET”), polybutylene terephthalate (“PBT”), polyethylene naphthalate (“PEN”), and polybutylene naphthalate (“PBN”). Additionally or alternatively, in some embodiments, the polyolefin is selected from the group consisting of poly(4 - methyl - 1 - pentene), poly(1 - butene), poly(1 - pentene), and poly(1 - hexene); preferably, the polyolefin is poly(4 - methyl - 1 - pentene).

[0009] In some embodiments, the polyester composition further comprises high D k / D f glass fiber. Additionally or alternatively, in some embodiments, the polyester weight ratio is from 75% to 93%.

[0010] In some embodiments, the polyester composition includes a D k not greater than 3.5 and a D f not greater than 0.003, as measured at 1 kHz according to ASTM D150. Additionally or alternatively, in some embodiments, the polyester composition includes a D k not greater than 3.4 and a D f not greater than 0.03, as measured at 1 MHz according to ASTM D150.

[0011] In some embodiments, the polyester composition includes a notched impact strength of at least 80 J / m as measured according to ASTM D256.

[0012] In another aspect, the present invention relates to a mobile electronic device component comprising the polyester composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a graph showing the normalized notched impact strength as a function of the PE weight ratio for (A) a polyester composition without glass fiber, (B) a polyester composition containing low D k / D f glass fiber as the sole glass fiber, and (C) a polyester composition containing a blend of low D k / D f glass fiber and high D k / D f glass fiber. DETAILED DESCRIPTION

[0014] This document describes a polyester composition comprising a semi-aromatic semi-crystalline polyester, a polyolefin, and glass fibers having a low dielectric constant (“D k ”) and a low dissipation factor (“Df”) (“low D k / D f glass fibers”). The concentrations of the semi-crystalline polyester and the polyolefin are selected such that the polyester weight ratio (the weight of the polyester in the composition relative to the total weight of the polyester and the polyolefin in the composition) is from 70% to 95%. It has surprisingly been found that when the polyester weight ratio is within the above range, the polyester composition has an excellent balance of dielectric properties (D k and D f ) and mechanical properties (e.g., notched impact strength). It has also surprisingly been found that when the polyester composition further comprises high D k / D f glass fibers, the balance of dielectric and mechanical properties is further improved when the polyester weight ratio is from 75% to 93%. At least in part due to the excellent balance of dielectric and mechanical properties, the polyester composition can desirably be incorporated into components of mobile electronic devices.

[0015] Unless otherwise explicitly restricted, the term “alkyl” and derivative terms such as “alkoxy”, “acyl”, and “alkylthio” as used herein include straight-chain, branched-chain, and cyclic moieties within their scope. Examples of alkyl are methyl, ethyl, 1-methylethyl, propyl, 1,1-dimethylethyl, and cyclopropyl. Unless otherwise explicitly specified, each alkyl and aryl can be unsubstituted or substituted by one or more substituents selected from, but not limited to, the following: halogen, hydroxy, sulfo, C1-C6 alkoxy, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, C 6- C 15 aryloxy or C6-C 15 aryl, provided that these substituents are sterically compatible and satisfy the rules of chemical bonding and strain energy. The term “halogen” or “halo group” includes fluorine, chlorine, bromine, and iodine, with fluorine being preferred.

[0016] The term "aryl" refers to phenyl, indanyl or naphthyl. An aryl may contain one or more alkyl groups and in such cases is sometimes referred to as "alkylaryl"; for example, it may be composed of an aromatic group and two C1-C6 groups (such as methyl or ethyl). An aryl may also contain one or more heteroatoms (e.g., N, O or S) and in such cases is sometimes referred to as "heteroaryl"; these heteroaromatic rings may be fused to other aromatic systems. Such heteroaromatic rings include, but are not limited to, furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, isoxazolyl, oxazolyl, thiazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl and triazinyl ring structures. An aryl or heteroaryl substituent may be unsubstituted or substituted with one or more substituents selected from, but not limited to, the following: halogen, hydroxy, C1-C6 alkoxy, sulfo, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, C6-C 15 aryloxy or C6-C 15 aryl, provided that these substituents are sterically compatible and satisfy the rules of chemical bonding and strain energy.

[0017] Polyester composition

[0018] The polyester composition described herein comprises a semi-aromatic semi-crystalline polyester, a polyolefin and low D k / D f glass fiber. In some embodiments, the polyester composition may comprise additional components. As pointed out above, it has unexpectedly been found that when the polyester weight ratio is from 70% to 95%, the polyester composition has an excellent balance of dielectric and mechanical properties. The polyester weight ratio is given by the formula:

[0019]

[0020] where W PE and W PO are the weights of the semi-aromatic semi-crystalline polyester and the polyolefin in the polyester composition, respectively. In some embodiments, the polyester weight ratio is at least 75%, at least 80% or at least 85%. In some embodiments, the polyester weight ratio is not greater than 93%. In some embodiments, the polyester weight ratio is from 75% to 95%, or from 80% to 95%, or from 85% to 95%, or from 75% to 93%, or from 80% to 93% or from 85% to 93%.

[0021] Also as mentioned above, it has also unexpectedly been found that when the polyester composition further comprises high D k / D f glass fiber, when the polyester weight ratio is from 75% to 93%, the balance of dielectric and mechanical properties is further improved. In some embodiments, in the polyester composition comprising additional high D k / D f In the case of glass fiber, the polyester composition has a polyester weight ratio of at least 75%, or at least 77%, or at least 80%, or at least 82%. In some embodiments, where the polyester composition comprises additional high D k / D f In the case of glass fiber, the polyester composition has a polyester weight ratio of not more than 93% or not more than 90%. In some embodiments, where the polyester composition comprises additional high D k / D f In the case of glass fiber, the polyester composition has a polyester weight ratio from 75% to 93%, or from 77% to 93%, or from 80% to 93%, or from 82% to 93%, or from 75% to 90%, or from 77% to 90%, or from 80% to 90%, or from 82% to 90%.

[0022] Regarding dielectric properties, in some embodiments, the polyester composition has a D not greater than 3.5, or not greater than 3.4 at 1 kHz k . In some embodiments, the polyester composition has a D of at least 2.8, or at least 2.9, or at least 3.0 k . In some embodiments, the polyester composition has a D from 2.8 to 3.5, or from 2.9 to 3.5, or from 3.0 to 3.5, or from 2.8 to 3.4, or from 2.9 to 3.4, or from 3.0 to 3.4 at 1 kHz k . In some embodiments, the polyester composition has a D not greater than 3.4, or not greater than 3.3 at 1 MHz k . In some embodiments, the polyester composition has a D of at least 2.8, or at least 2.9, or at least 3.0 at 1 MHz k . In some embodiments, the polyester composition has a D from 2.8 to 3.4, or from 2.9 to 3.4, or from 3.0 to 3.4, or from 2.8 to 3.3, or from 2.9 to 3.3, or from 3.0 to 3.3 at 1 MHz k . In some embodiments, the polyester composition has a D within the respective ranges above at both 1 kHz and 1 MHz k . The D at 1 kHz and 1 MHz k can be measured according to ASTM D150.

[0023] In some embodiments, the polyester composition has a D not greater than 0.003, or not greater than 0.002 at 1 kHz f . In some embodiments, the polyester composition has a D of at least 0.0005, or at least 0.001, or at least 0.0014 at 1 kHz f。In some embodiments, the polyester composition has a D of from 0.0005 to 0.003, or from 0.001 to 0.003, or from 0.0014 to 0.003, or from 0.0005 to 0.002, or from 0.001 to 0.002, or from 0.0014 to 0.002 at 1 kHz f 。In some embodiments, the polyester composition has a D of not greater than 0.03, or not greater than 0.02 at 1 MHz f 。In some embodiments, the polyester composition has a D of at least 0.001 or at least 0.005 at 1 MHz f 。In some embodiments, the polyester composition has a D of from 0.001 to 0.03, or from 0.005 to 0.03, or from 0.001 to 0.02, or from 0.005 to 0.02 at 1 MHz f 。In some embodiments, the polyester composition has a D within the respective ranges above at both 1 kHz and 1 MHz f 。The D at 1 kHz and 1 MHz f can be measured according to ASTM D150

[0024] In some embodiments, the polyester composition has a D of not greater than 3.5, or not greater than 3.3, or not greater than 3.25 at 1.77 GHz k 。In some embodiments, the polyester composition has a D of not less than 2.7, or not less than 2.8, or not less than 2.9 at 1.77 GHz k 。In some embodiments, the polyester composition has a D of from 2.7 to 3.5, or from 2.7 to 3.3, or from 2.7 to 3.25, or from 2.8 to 3.5, or from 2.8 to 3.3, or from 2.9 to 3.3, or from 2.9 to 3.5, or from 2.9 to 3.3, or from 2.9 to 3.25 at 1.77 GHz k 。In some embodiments, the polyester composition has a D of not greater than 0.008, or not greater than 0.007, or not greater than 0.065 at 1.77 GHz f 。In some embodiments, the polyester composition has a D of not less than 0.003, or not less than 0.004, or not less than 0.0045 at 1.77 GHz f 。In some embodiments, the polyester composition has a D of from 0.003 to 0.008, or from 0.004 to 0.008, or from 0.0045 to 0.008, or from 0.003 to 0.007, or from 0.004 to 0.007, or from 0.0045 to 0.007, or from 0.003 to 0.0065, or from 0.004 to 0.0065, or from 0.0045 to 0.0065 at 1.77 GHz f。D at 1.77 GHz k and D f can be measured according to ASTM D2520.

[0025] In some embodiments, the polyester composition has a D that is no greater than 3.3, or no greater than 3.2, or no greater than 3.1 at 2.45 GHz k 。In some embodiments, the polyester composition has a D that is no less than 2.6, or no less than 2.7, or no less than 2.8 at 2.4 GHz k 。In some embodiments, the polyester composition has a D that ranges from 2.6 to 3.3, or from 2.7 to 3.3, or from 2.8 to 3.3, or from 2.6 to 3.2, or from 2.7 to 3.2, or from 2.8 to 3.3, or from 2.6 to 3.1, or from 2.7 to 3.1, or from 2.8 to 3.1 at 2.45 GHz k 。In some embodiments, the polyester composition has a D that is no greater than 0.008, or no greater than 0.007, or no greater than 0.006 at 2.45 GHz f 。In some embodiments, the polyester composition has a D that is no less than 0.003, or no less than 0.004, or no less than 0.0045 at 2.45 GHz f 。In some embodiments, the polyester composition has a D that ranges from 0.003 to 0.008, or from 0.004 to 0.008, or from 0.0045 to 0.008, or from 0.003 to 0.007, or from 0.004 to 0.007, or from 0.0045 to 0.007, or from 0.003 to 0.006, or from 0.004 to 0.006, or from 0.0045 to 0.006 at 2.45 GHz f 。D at 2.45 GHz k and D f can be measured according to ASTM D2520.

[0026] Regarding mechanical properties, in some embodiments, the polyester composition has a notched impact strength of at least 80 J / m, or at least 90 J / m, or at least 100 J / m, or at least 110 J / m. In some embodiments, the polyester composition has a notched impact strength of not greater than 140 J / m, or not greater than 130 J / m, or not greater than 120 J / m, or not greater than 115 J / m. In some embodiments, the polyester composition has a notched impact strength ranging from 80 J / m to 140 J / m, or from 90 J / m to 140 J / m, or from 100 J / m to 140 J / m, or from 110 J / m to 140 J / m, or from 80 J / m to 130 J / m, or from 90 J / m to 130 J / m, or from 100 J / m to 130 J / m, or from 110 J / m to 130 J / m, or from 80 J / m to 120 J / m, or from 90 J / m to 120 J / m, or from 100 J / m to 120 J / m, or from 110 J / m to 120 J / m, or from 80 J / m to 115 J / m, or from 90 J / m to 115 J / m, or from 100 J / m to 115 J / m, or from 110 J / m to 115 J / m, and the notched impact strength can be measured according to ASTM D256.

[0027] In some embodiments, based on the total weight of the polyester composition, the total concentration of the semi-aromatic semi-crystalline polyester and the polyolefin in the polyester composition is at least 55 weight percent (“wt.%”), or at least 60 wt.%, or at least 65 wt.%. In some embodiments, the total concentration of the semi-aromatic semi-crystalline polyester and the polyolefin in the polyester composition is not greater than 85 wt.%, or not greater than 80 wt.%, or not greater than 75 wt.%. In some embodiments, the total concentration of the semi-aromatic semi-crystalline polyester and the polyolefin in the polyester composition ranges from 55 wt.% to 85 wt.%, or from 55 wt.% to 80 wt.%, or from 55 wt.% to 75 wt.%, or from 60 wt.% to 85 wt.%, or from 60 wt.% to 80 wt.%, or from 60 wt.% to 75 wt.%, or from 65 wt.% to 85 wt.%, or from 65 wt.% to 80 wt.%, or from 65 wt.% to 75 wt.%. As used herein, unless otherwise expressly indicated, wt.% is relative to the total weight of the polyester composition.

[0028] In some embodiments, the polyester composition consists essentially of a semi-aromatic semi-crystalline polyester, a polyolefin, and a low D k / D f glass fiber (or a low D k / D f glass fiber and a high D k / D fcomposed of a blend of glass fibers). In such embodiments, based on the total weight of the polyester composition, the total concentration of the above components is at least 95 wt.%, or at least 97 wt.%, or at least 98 wt.%, or at least 99 wt.%, or at least 99.5 wt.%, or at least 99.9 wt.%. In some embodiments, the polyester composition comprises one or more additional semi-aromatic semi-crystalline polyesters or one or more additional polyolefins. In some such embodiments, each additional semi-aromatic semi-crystalline polyester and each additional polyolefin are different and are as described below. In one such embodiment, the polyester composition consists essentially of: a semi-aromatic semi-crystalline polyester and one or more additional semi-aromatic semi-crystalline polyesters; a polyolefin and one or more additional polyolefins; and low D k / D f glass fibers (or low D k / D f glass fibers and high D k / D f a blend of glass fibers). That is, in such embodiments, the total concentration of the semi-aromatic semi-crystalline polyester, the polyolefin, and the low D k / D f glass fibers (or low D k / D f glass fibers and high D k / D f a blend of glass fibers) is at least 95 wt.%, or at least 97 wt.%, or at least 98 wt.%, or at least 99 wt.%, or at least 99.5 wt.%, or at least 99.9 wt.%.

[0029] Semi-aromatic semi-crystalline polyester

[0030] The polyester composition comprises a semi-aromatic semi-crystalline polyester. As used herein, a "semi-aromatic" polyester refers to any polymer comprising at least 50 mol% of repeating units R PE having at least one ester group (-C(O)O-) and at least one aryl group. Further as used herein, a "semi-crystalline" polyester (or "semi-crystalline" polymer) is a polyester (or polymer) having a heat of fusion ("ΔH f ") of at least 5 joules per gram ("J / g") at a heating rate of 20 °C / min (an amorphous polyester (or polymer) has a ΔH f ) less than 5 J / g at a heating rate of 20 °C / min). ΔH fIt can be measured according to ASTM D3418. In some embodiments, the semi-aromatic semi-crystalline polyester comprises at least 60 mol%, or at least 70 mol%, or at least 80 mol%, or at least 90 mol%, or at least 95 mol%, or at least 99 mol%, or at least 99.9 mol% of the repeating unit R PE . As used herein, unless otherwise expressly stated, mol% is relative to the total number of repeating units in the indicated polymer (e.g., the semi-aromatic semi-crystalline polyester).

[0031] In some embodiments, the repeating unit R PE is represented by the following formula:

[0032]

[0033] wherein T is a C1-C 18 alkyl group and Ar is an aryl group. Preferably, Ar is a phenyl group or a naphthyl group. More preferably, Ar is a phenyl group and the -COOH groups shown in formulas (1) to (3) are arranged in the meta position (1,4-) with respect to Ar. In some embodiments, R PE is represented by any one of the following formulas:

[0034] and

[0035]

[0036] wherein R1 to R4, at each position, are independently selected from the group consisting of hydrogen and C1-C 12 alkyl groups, and q, n, and m are independently selected integers from 1 to 12. In some embodiments, R1 to R4 are all hydrogen. In some embodiments, q is an integer from 3 to 10, preferably from 3 to 5, most preferably 3 or 4. In some embodiments, n = m. Preferably, n and m are 1.

[0037] In some embodiments, the semi-aromatic semi-crystalline polyester is selected from the group consisting of polycyclohexylene dimethylene terephthalate (“PCT”), polyethylene terephthalate (“PET”), polybutylene terephthalate (“PBT”), polyethylene naphthalate (“PEN”), and polybutylene naphthalate (“PBN”). Preferably, the semi-aromatic semi-crystalline polyester is PBT or PEN.

[0038] Of course, in some embodiments, the semi-aromatic semi-crystalline polyester has additional repeating units different from R PE . In some such embodiments, the semi-aromatic semi-crystalline polyester has one or more additional repeating units R* PE , each different from one another and different from R PE。In one such embodiment, each repeating unit R* PE is represented by a formula selected from the group of formulas consisting of formulas (1) to (3). In some embodiments, relative to the total number of repeating units in the semi-aromatic semi-crystalline polyester, the repeating unit R PE and one or more additional repeating units R* PE have a total concentration of at least 60 mol%, or at least 70 mol%, or at least 80 mol%, or at least 90 mol%, or at least 95 mol%, or at least 99 mol%, or at least 99.5 mol%, or 100 mol%.

[0039] In some embodiments, the semi-aromatic semi-crystalline polyester has an intrinsic viscosity of from about 0.4 to about 2.0 deciliters per gram ("dl / g") as measured in a 60:40 phenol / tetrachloroethane mixture or a similar solvent at about 30 °C. Preferably, the semi-aromatic semi-crystalline polyester has an intrinsic viscosity of 0.5 to 1.4 dl / g. The intrinsic viscosity can be measured according to ASTM D 5225.

[0040] In some embodiments, the semi-aromatic semi-crystalline polyester has a number average molecular weight (“Mn”) of at least about 1,000 g / mol, or at least about 5,000 g / mol, or at least about 10,000 g / mol. In some embodiments, the semi-aromatic semi-crystalline polyester has an Mn of no greater than about 100,000 g / mol, or no greater than about 75,000 g / mol, or no greater than about 50,000 g / mol. In some embodiments, the semi-aromatic semi-crystalline polyester has an Mn ranging from 1,000 g / mol to 50,000 g / mol, or from 5,000 g / mol to 75,000 g / mol, or from 10,000 g / mol to 50,000 g / mol. In some embodiments, the semi-aromatic semi-crystalline polyester has a weight average molecular weight (“Mw”) of at least about 1,000 g / mol, or at least about 15,000 g / mol, or at least about 20,000 g / mol. In some embodiments, the semi-aromatic semi-crystalline polyester has an Mw of no greater than about 200,000 g / mol, or no greater than about 150,000 g / mol, or no greater than about 125,000 g / mol, or no greater than about 110,000 g / mol, or no greater than about 100,000 g / mol. In some embodiments, the semi-aromatic semi-crystalline polyester has an Mw ranging from 1,000 g / mol to 200,000 g / mol, or from 15,000 g / mol to 200,000 g / mol, or from 20,000 g / mol to 200,000 g / mol, or from 20,000 g / mol to 150,000 g / mol, or from 20,000 g / mol to 125,000 g / mol, or from 20,000 g / mol to 110,000 g / mol, or from 20,000 g / mol to 100,000 g / mol. Mn and Mw can be determined by gel permeation chromatography (GPC) using ASTM D5296 with polystyrene standards.

[0041] In some embodiments, the semi-aromatic semi-crystalline polyester has a Tm of at least 210 °C, preferably at least 220 °C, more preferably at least 230 °C and most preferably at least 240 °C. In some embodiments, the semi-aromatic semi-crystalline polyester has a Tm of at most 350 °C, preferably at most 340 °C, more preferably at most 330 °C and most preferably at most 320 °C. In some embodiments, the semi-aromatic semi-crystalline polyester has a Tm ranging from 210 °C to 350 °C, or from 220 °C to 340 °C, or from 230 °C to 330 °C, or from 240 °C to 320 °C. In some embodiments, the semi-aromatic semi-crystalline polyester has a glass transition temperature (“Tg”) of at least 60 °C, or at least 70 °C, or at least 80 °C. In some embodiments, the semi-aromatic semi-crystalline polyester has a Tg not greater than 180 °C, or not greater than 160 °C, or not greater than 140 °C. In some embodiments, the semi-aromatic semi-crystalline polyester has a Tg ranging from 60 °C to 180 °C, or from 70 °C to 160 °C, or from 80 °C to 140 °C.

[0042] In some embodiments, based on the total weight of the polyester composition, the concentration of the semi-aromatic semi-crystalline polyester in the polyester composition is at least 30 wt.%, or at least 35 wt.%, or at least 40 wt.%, or at least 45 wt.%. In some embodiments, the concentration of the semi-aromatic semi-crystalline polyester in the polyester composition is not greater than 80 wt.%, or not greater than 75 wt.%, or not greater than 70 wt.%, or not greater than 65 wt.%. In some embodiments, the concentration of the semi-aromatic semi-crystalline polyester in the polyester composition ranges from 30 wt.% to 80 wt.%, or from 40 wt.% to 75 wt.%, or from 45 wt.% to 70 wt.%, or from 45 wt.% to 65 wt.%.

[0043] In some embodiments, the polyester composition comprises one or more additional semi-aromatic semi-crystalline polyesters, each different from one another and different from the semi-aromatic semi-crystalline polyester. In some such embodiments, the total concentration of the semi-aromatic semi-crystalline polyesters is within the ranges given above for the semi-aromatic semi-crystalline polyester. In alternative embodiments, the concentration of each semi-aromatic semi-crystalline polyester is within the ranges given above for the semi-aromatic semi-crystalline polyester.

[0044] Polyolefin

[0045] The polyester composition comprises a polyolefin having a repeating unit R PO which repeating unit contains at least 4 carbon atoms and is represented by the formula:

[0046]

[0047] wherein R5 to R8 are independently selected from the group consisting of hydrogen and C1-C 10 alkyl groups. Preferably, the repeating unit (RPO ) contains at least 5 carbon atoms. In some embodiments, the polyolefin contains at least 50 mol%, or at least 60 mol%, or at least 70 mol%, or at least 80 mol%, or at least 90 mol%, or at least 95 mol%, or at least 99 mol%, or at least 99.5 mol% of the repeating unit (R PO ), where mol% is relative to the total number of repeating units in the polyolefin. In some embodiments, R6 to R8 are all hydrogen. Of course, in such embodiments, R5 is a C5-C 10 alkyl group.

[0048] Of course, in some embodiments, the polyolefin has additional repeating units different from (R PO ). In some such embodiments, the polyolefin has one or more additional repeating units R* PO , each different from one another and different from (R PO ). In one such embodiment, each repeating unit R* PO is represented by formula (4).

[0049] In some embodiments, the polyolefin is selected from the group consisting of poly(4-methyl-1-pentene) (also known as polymethylpentene), poly(1-butene), poly(1-pentene), poly(1-hexene), and mixtures of any two or more thereof. Preferably, the polyolefin is poly(4-methyl-1-pentene).

[0050] In some embodiments, the polyolefin has a number average molecular weight of less than 1,000,000 g / mol, preferably less than 500,000 g / mol, and most preferably less than 200,000 g / mol. In some embodiments, the polyolefin has a weight average molecular weight of less than 2,000,000 g / mol, preferably less than 1,000,000 g / mol, and most preferably less than 300,000 g / mol. The number average molecular weight can be measured according to ASTM D5296.

[0051] In some embodiments, the polyolefin has a melt flow rate (“MFR”) at 260 °C under 2.16 Kg of from 5 g / 10 min. to 250 g / 10 min., or from 10 g / 10 min. to 200 g / 10 min., or from 15 g / 10 min. to 150 g / 10 min., or from 20 g / 10 min. to 100 g / 10 min., or from 25 g / 10 min. to 50 g / 10 min., or from 30 g / 10 min. to 40 g / 10 min. In some embodiments, the polyolefin has an MFR of at least 3 g / 10 min. at 250 °C under 2.16 Kg or 5 Kg. The MFR can be measured according to ASTM D1238. In some embodiments, the polyolefin has a viscous melt flow at 30 °C to 70 °C above its melting point. The polyolefin has a uniform and continuous melt above its melting temperature. The polyolefin can be processed by injection molding at 30 °C to 80 °C above its melting temperature.

[0052] In some embodiments, the polyolefin has a melting temperature (“Tm”) of at least 170 °C, or at least 180 °C, or at least 190 °C, or at least 200 °C, or at least 210 °C. In some embodiments, the polyolefin has a Tm of not greater than 270 °C, or not greater than 260 °C, or not greater than 250 °C, or not greater than 240 °C. In some embodiments, the polyolefin has a Tm of from 170 °C to 270 °C, or from 180 °C to 260 °C, or from 190 °C to 250 °C, or from 200 °C to 240 °C, or from 210 °C to 240 °C. In some embodiments, the polyolefin has a glass transition temperature (“Tg”) of at least 0 °C, or at least 10 °C, or at least 20 °C, or at least 30 °C, or at least 35 °C, or at least 40 °C. In some embodiments, the polyolefin has a Tg of not greater than 80 °C, or not greater than 70 °C, or not greater than 65 °C, or not greater than 60 °C. In some embodiments, the polyolefin has a Tg of from 0 °C to 80 °C, or from 10 °C to 70 °C, or from 20 °C to 65 °C, or from 30 °C to 60 °C, or from 35 °C to 60 °C, or from 40 °C to 60 °C. The Tm and Tg can be measured by differential scanning calorimetry (“DSC”) according to ASTM D3418.

[0053] In some embodiments, based on the total weight of the polyester composition, the concentration of polyolefin in the polyester composition is at least 1 wt.%, or at least 3 wt.%, or at least 4 wt.%, or at least 5 wt.%. In some embodiments, based on the total weight of the polyester composition, the concentration of polyolefin in the polyester composition is not greater than 40 wt.%, or not greater than 30 wt.%, or not greater than 25 wt.%, or not greater than 20 wt.%. In some embodiments, the concentration of polyolefin in the polyester composition is from 1 wt.% to 40 wt.%, or from 3 wt.% to 30 wt.%, or from 4 wt.% to 25 wt.%, or from 5 wt.% to 20 wt.%.

[0054] In some embodiments, the polyester composition comprises one or more additional polyolefins, each different from one another and different from the polyolefin. In some such embodiments, the total concentration of polyolefins is within the ranges given above for polyolefin. In alternative embodiments, the concentration of each polyolefin is within the ranges given above for polyolefin.

[0055] Glass fiber

[0056] The polyester composition comprises low D k / D f glass fiber, and in some embodiments, high D k / D f glass fiber of additional glass fiber. Generally speaking, in terms of composition, glass fiber is a silica-based glass compound containing several metal oxides, which can be customized to produce different types of glass. The main oxide is silica in the form of silica sand; other oxides (such as calcium, sodium and aluminum) are incorporated to lower the melting temperature and hinder crystallization. Glass fiber can be added as continuous fiber or chopped glass fiber. Glass fiber typically has an equivalent diameter from 5 to 20 μm, preferably from 5 to 15 μm, more preferably from 5 to 10 μm. All types of glass fiber can be used, such as A, C, D, E, M, R, S, T glass fiber (as described in John Murphy's Additives for Plastics Handbook, 2nd Edition, Chapter 5.2.3, pages 43 - 48) and any mixture thereof.

[0057] E, R, S, and T glass fibers are well-known in the art. They are notably described in Fiberglass and Glass Technology, Wallenberger, Frederick T.; Bingham, Paul A. (eds.), 2010, XIV, Chapter 5, pp. 197-225. R, S, and T glass fibers are substantially composed of oxides of silicon, aluminum, and magnesium. Specifically, these glass fibers typically contain from 62-75 wt.% SiO2, from 16-28 wt.% Al2O3, and from 5-14 wt.% MgO. On the other hand, R, S, and T glass fibers contain less than 10 wt.% CaO.

[0058] In some embodiments, the glass fibers (whether low D k / D f glass fibers or high D k / D f glass fibers) are high modulus glass fibers. High modulus glass fibers have a modulus of elasticity of at least 76 GPa, preferably at least 78 GPa, more preferably at least 80 GPa, and most preferably at least 82 GPa as measured according to ASTM D2343. Examples of high modulus glass fibers include, but are not limited to, S, R, and T glass fibers. For example, commercially available high modulus glass fibers are S-1 and S-2 glass fibers from Taishan Company and AGY Company, respectively. In some embodiments, the glass fibers are high modulus and low D k / D f glass fibers.

[0059] The morphology of the glass fibers (whether low D k / D f glass fibers or high D k / D f glass fibers) is not particularly limited. The glass fibers can have a circular cross-section ("circular glass fibers") or a non-circular cross-section ("flat glass fibers"). The cross-section is taken in a plane perpendicular to the length of the glass fiber. The non-circular cross-section has a large dimension (corresponding to the longest dimension in the cross-section) and a small dimension (perpendicular to both the large dimension and the length of the glass fiber). The non-circular cross-section can be, but is not limited to, oval, elliptical, or rectangular.

[0060] In some embodiments where the glass fiber is a flat glass fiber, the major dimension of the non-circular cross-section is preferably at least 15 μm, more preferably at least 20 μm, even more preferably at least 22 μm, most preferably at least 25 μm, and / or preferably at most 40 μm, more preferably at most 35 μm, even more preferably at most 32 μm, most preferably at most 30 μm. In some embodiments, the major dimension of the non-circular cross-section is in the range from 15 to 35 μm, preferably from 20 to 30 μm, more preferably from 25 to 29 μm. In some embodiments where the glass fiber is a flat glass fiber, the minor dimension of the non-circular cross-section is preferably at least 4 μm, more preferably at least 5 μm, even more preferably at least 6 μm, most preferably at least 7 μm, and / or preferably at most 25 μm, more preferably at most 20 μm, even more preferably at most 17 μm, most preferably at most 15 μm. In some embodiments, the minor dimension of the non-circular cross-section is in the range from 5 to 20, preferably from 5 to 15 μm, more preferably from 7 to 11 μm. In some embodiments where the glass fiber is a flat glass fiber, the flat glass fiber has an aspect ratio of preferably at least 2, more preferably at least 2.2, even more preferably at least 2.4, most preferably at least 3, and / or preferably at most 8, more preferably at most 6, even more preferably at most 4. In some embodiments, the flat glass fiber has an aspect ratio in the range from 2 to 6, preferably from 2.2 to 4. The aspect ratio is defined as the ratio of the major dimension of the cross-section of the flat glass fiber to the minor dimension of the same cross-section. The aspect ratio can be measured according to ISO 1888.

[0061] In some embodiments where the glass fiber is a round glass fiber, the round glass fiber has an aspect ratio of preferably less than 2, more preferably less than 1.5, even more preferably less than 1.2, still more preferably less than 1.1, most preferably less than 1.05. Of course, those of ordinary skill in the art will understand that, regardless of the morphology of the glass fiber (e.g., round or flat), by definition the aspect ratio cannot be less than 1.

[0062] Low D in the polyester composition k / D f The glass fiber has a Dk of no greater than 5.5, or no greater than 5.4, or no greater than 5.3, or no greater than 5.2, or no greater than 5.1, or no greater than 5.0 at 1 MHz. Additionally, in some embodiments, low D k / D f The glass fiber has a Dk of at least 3.7, or at least 3.8, or at least 3.9, or at least 4.0 at 1 MHz. In some embodiments, low D k / D fThe glass fiber has a Dk of from 3.7 to 5.5, or from 3.7 to 5.4, or from 3.7 to 5.3, or from 3.7 to 5.2, or from 3.7 to 5.1, or from 3.7 to 5.0, or from 3.8 to 5.0, or from 3.9 to 5.0, or from 4.0 to 5.0 at 1 MHz. Low D k / D f The glass fiber also has a Df of not greater than 0.002 or not greater than 0.001 at 1 MHz. Additionally, in some embodiments, low D k / D f The glass fiber has a D of not less than 0.0001 or not less than 0.0005 f . In some embodiments, low D k / D f The glass fiber has a D of from 0.0001 to 0.002 or from 0.0005 to 0.001 f . The D k and D f at 1 MHz can be measured according to ASTM D150.

[0063] In some embodiments, based on the total weight of the polyester composition, the concentration of the low D k / D f glass fiber in the polyester composition is at least 10 wt.%, or at least 15 wt.%, or at least 20 wt.%, or at least 25 wt.%. Additionally or alternatively, in some embodiments, based on the total weight of the polyester composition, the concentration of the low D k / D f glass fiber in the polyester composition is not greater than 60 wt.%, not greater than 50 wt.%, or not greater than 45 wt.%, or not greater than 40 wt.%, or not greater than 35 wt.%. In some embodiments, the concentration of the low D k / D f glass fiber in the polyester composition is from 10 wt.% to 60 wt.%, or from 15 wt.% to 50 wt.%, or from 15 wt.% to 45 wt.%, or from 15 wt.% to 40 wt.%, or from 20 wt.% to 40 wt.%, or from 20 wt.% to 35 wt.%.

[0064] As noted above, in some embodiments, the polyester composition comprises additional high D k / D f glass fibers. The high D k / D f glass fibers have a D greater than 5.0, or greater than 5.1, or greater than 5.2, or greater than 5.3, or greater than 5.4 at 1 MHz k , and a D greater than 0.001 or greater than 0.002 at 1 MHzf In some embodiments, the polyester composition comprises high D k / D f glass fiber, based on the total weight of the polyester composition, the concentration of high D k / D f glass fiber in the polyester composition is at least 0.4 wt.%, or at least 0.5 wt.%, or at least 1 wt.%, or at least 2 wt.%. In some embodiments, the high D k / D f glass fiber concentration in the polyester composition is not greater than 10 wt.%, or not greater than 5 wt.%, or not greater than 4 wt.%. In some embodiments, the high D k / D f glass fiber concentration in the polyester composition is from 0.4 wt.% to 10 wt.%, or from 0.5 wt.% to 10 wt.%, or from 1 wt.% to 10 wt.%, or from 2 wt.% to 10 wt.%, or from 0.4 wt.% to 5 wt.%, or from 0.5 wt.% to 5 wt.%, or from 1 wt.% to 5 wt.%, or from 2 wt.% to 5 wt.%, or from 0.4 wt.% to 4 wt.%, or from 0.5 wt.% to 4 wt.%, or from 1 wt.% to 4 wt.%, or from 2 wt.% to 4 wt.%.

[0065] In those embodiments where the polyester composition comprises low D k / D f glass fiber and high D k / D f glass fiber, the total concentration of glass fiber in the polyester composition is within the range given above for low D k / D f glass fiber. In some embodiments, the total concentration of each of low D k / D f glass fiber and high D k / D f glass fiber is independently within the range given above for low D k / D f glass fiber.

[0066] Additional components

[0067] As noted above, in some embodiments, in addition to the semi-aromatic semi-crystalline polyester, polyolefin, low D k / D f glass fiber and high D k / D fIn addition to the glass fiber, the polyester composition may further comprise additional components. In some embodiments, each additional component may be selected from the group consisting of a reinforcing agent, a toughening agent, a plasticizer, a colorant, a pigment, an antistatic agent, a dye, a lubricant, a heat stabilizer, a light stabilizer, a flame retardant, a nucleating agent, and an antioxidant.

[0068] Regarding the reinforcing agent, as used herein in the context of additional components, the term does not include glass fiber. The reinforcing agent may be selected from fibrous reinforcing agents and particulate reinforcing agents. A fibrous reinforcing agent is herein considered to be a material having a length, a width, and a thickness, wherein the average length is significantly greater than both the width and the thickness. Generally, such a material has an aspect ratio (defined as the average ratio between the length and the largest of the width and the thickness) of at least 5, at least 10, at least 20, or at least 50. In some embodiments, the fibrous reinforcing agent (e.g., carbon fiber) has an average length from 3 mm to 50 mm. In some such embodiments, the fibrous reinforcing agent has an average length from 3 mm to 10 mm, or from 3 mm to 8 mm, or from 3 mm to 6 mm, or from 3 mm to 5 mm. In alternative embodiments, the fibrous reinforcing agent has an average length from 10 mm to 50 mm, or from 10 mm to 45 mm, or from 10 mm to 35 mm, or from 10 mm to 30 mm, or from 10 mm to 25 mm, or from 15 mm to 25 mm. The average length of the fibrous reinforcing agent may be taken as the average length of the fibrous reinforcing agent before incorporation into the polyester composition or may be taken as the average length of the fibrous reinforcing agent in the polyester composition.

[0069] In some embodiments, the fibrous reinforcing agent is selected from the group consisting of mineral fillers (such as talc, mica, kaolin, calcium carbonate, calcium silicate, magnesium carbonate), carbon fibers, synthetic polymer fibers, aramid fibers, aluminum fibers, titanium fibers, magnesium fibers, boron carbide fibers, rock wool fibers, steel fibers, and wollastonite.

[0070] In some embodiments, the polyester composition does not contain hollow reinforcing agents. Hollow reinforcing agents include, but are not limited to, hollow glass fibers and glass bubbles. As used herein, "does not contain" a component means that the polyester composition has a concentration of the specified component of less than 5 wt.%, or less than 2 wt.%, or less than 1 wt.%, or less than 0.1 wt.%, or less than 0.05 wt.%, or less than 0.001 wt.%, or even undetectable. Generally, hollow reinforcing agents undesirably reduce the mechanical properties (e.g., notched impact strength) of the polyester composition.

[0071] Regarding the toughening agent, they are typically low-Tg polymers. For example, in some embodiments, the toughening agent has a Tg less than room temperature, or less than 0 °C, or even less than -25 °C. Due to its low Tg, the toughening agent is typically elastomeric at room temperature. The toughening agent may be a functionalized polymer backbone.

[0072] The polymer backbone of the toughening agent can be selected from elastomeric backbones, which include polyethylene and its copolymers, such as ethylene-butene; ethylene-octene; polypropylene and its copolymers; polybutene; polyisoprene; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-acrylate rubber; butadiene-acrylonitrile rubber, ethylene-acrylic acid (EAA), ethylene-vinyl acetate (EVA); acrylonitrile-butadiene-styrene rubber (ABS), block copolymer styrene-ethylene-butylene-styrene (SEBS); block copolymer styrene-butadiene-styrene (SBS); core-shell elastomers of the methacrylate-butadiene-styrene (MBS) type, or a mixture of one or more of the above.

[0073] When the toughening agent is functionalized, the functionalization of the backbone can be produced by copolymerization including functionalized monomers, or by grafting the polymer backbone with another component.

[0074] Specific examples of functionalized toughening agents are especially terpolymers of ethylene, acrylate and glycidyl methacrylate, copolymers of ethylene and butyl acrylate; copolymers of ethylene, butyl acrylate and glycidyl methacrylate; ethylene-maleic anhydride copolymers; EPR grafted with maleic anhydride; styrene copolymers grafted with maleic anhydride; SEBS copolymers grafted with maleic anhydride; styrene-acrylonitrile copolymers grafted with maleic anhydride; ABS copolymers grafted with maleic anhydride.

[0075] The toughening agent can be present in the polyester composition in an amount greater than 1 wt.%, or greater than 2 wt.%, or greater than 3 wt.% based on the total weight of the polyester composition. The toughening agent can be present in the polyester composition in an amount less than 30 wt.%, or less than 20 wt.%, or less than 15 wt.%, or less than 10 wt.% based on the total weight of the polyester composition. In some embodiments, the toughening agent is present in the polyester composition in an amount from 1 wt.% to 30 wt.%, or from 2 wt.% to 20 wt.%, or from 3 wt.% to 15 wt.%. In some embodiments, the polyester composition does not contain a toughening agent.

[0076] The polyester composition can also contain other conventional additives commonly used in the art, including plasticizers, colorants, pigments (e.g., black pigments such as carbon black and aniline black), antistatic agents, dyes, lubricants (e.g., linear low density polyethylene, calcium stearate or magnesium stearate or sodium lignosulfonate), heat stabilizers, light stabilizers, flame retardants, nucleating agents, and antioxidants.

[0077] Preparation of polyester composition

[0078] The polyester composition can be manufactured by methods well known in the art. For example, in some embodiments, the polyester composition can be formed by melt blending a semi-aromatic semi-crystalline polyester, a polyolefin, a low D k / D f glass fiber, and additional components as described above.

[0079] Any suitable melt blending method can be used to mix the polymer components and the non-polymer components. For example, the polymer components and the non-polymer components can be fed into a melt mixer (such as a single-screw extruder or a twin-screw extruder, a blender, a single-screw or twin-screw kneader, or a Banbury mixer), and the addition step can be to add all the components at once or in batches step by step. When adding the polymer components and the non-polymer components in batches step by step, a part of these polymer components and / or non-polymer components is added first, and then melt blended with the remaining polymer components and non-polymer components added subsequently until a well-mixed composition is obtained. If the reinforcing agent presents a long physical shape (e.g., long fibers), then stretch-extrusion molding can be used to prepare the reinforced composition.

[0080] Articles and applications

[0081] At least in part due to the excellent balance of dielectric and mechanical properties, the polyester composition can desirably be incorporated into components of mobile electronic devices.

[0082] As used herein, a "mobile electronic device" refers to an electronic device that is intended to be conveniently transported and used in different locations. Mobile electronic devices can include, but are not limited to, mobile phones, personal digital assistants ("PDAs"), laptop computers, tablet computers, wearable computing devices (e.g., smart watches, smart glasses, etc.), cameras, portable audio players, portable radios, global positioning system receivers, and portable game consoles.

[0083] Components of mobile electronic devices can include, for example, radio antennas and the polyester composition. In this case, the radio antenna can be a WiFi antenna or an RFID antenna. Components of mobile electronic devices can also be antenna housings.

[0084] In some embodiments, the mobile electronic device component is an antenna housing. In some such embodiments, at least a portion of the radio antenna is disposed on the polyester composition. Additionally or alternatively, at least a portion of the radio antenna may be removed from the polyester composition. In some embodiments, the mobile electronic device component may be a mounting component having mounting holes or other fastening means, the other fastening means including but not limited to snap-fit connectors between itself and another component of the mobile electronic device, the other component including but not limited to a circuit board, microphone, speaker, display, battery, cover, housing, electrical or electronic connector, hinge, radio antenna, switch, or switchpad. In some embodiments, the mobile electronic device component may be at least a portion of an input device. In some embodiments, the mobile electronic device component may be a frame (e.g., a mobile phone or tablet frame) or a frame component.

[0085] The article can be molded from the polyester composition by any method suitable for thermoplastics (e.g., extrusion, injection molding, blow molding, rotational molding, or compression molding).

[0086] The article can be printed from the polyester composition by a method including a step of extruding the material (which is in the form of filaments, for example), or a step of laser sintering the material (which is in the form of powder in this case).

[0087] The polyester composition can also be incorporated into a method for manufacturing a three-dimensional (3D) object using an additive manufacturing system, the method comprising:

[0088] - providing a part material comprising the polyester composition, and

[0089] - printing a layer of the three-dimensional object from the part material.

[0090] Thus, the polyester composition can be in the form of a wire or filament for use in a 3D printing process, e.g., fused filament fabrication (also known as fused deposition modeling (“FDM”)).

[0091] The polyester composition can also be in the form of a powder (e.g., a substantially spherical powder) for use in a 3D printing process, e.g., selective laser sintering (“SLS”).

[0092] Uses of polyester composition and articles

[0093] The polyester composition and the article can be used to manufacture mobile electronic device components as described above.

[0094] The present invention also relates to the use of the polyester composition as described above for 3D printing objects.

[0095] Examples

[0096] These examples demonstrate the dielectric and mechanical properties of the polyester compositions. In these examples, the following components were used:

[0097] - Polybutylene terephthalate ("PBT") (polyester) : PBT in pellet form, sold under the trade name Celanex / Celanex was purchased from Celanese Corporation.

[0098] - Polyethylene naphthalate ("PEN") (polyester) : PEN in pellet form was purchased from

[0099] - Polymethylpentene ("PMP") (polyolefin) : PMP was obtained from RTP or Orida TM obtained.

[0100] - Glass fiber 1 ("GF 1") : Low D k / D f glass fiber, sold under the trade name CS(HL)301HP TM was commercially available from Chongqing Polycomp International Corp., with a D less than 5.0 and a D less than 0.002 as measured according to ASTM D150 at 1 MHz k and a D less than 0.002 f .

[0101] - Glass fiber 2 ("GF 2") : High D k / D f E-glass fiber.

[0102] - Additives : Nucleating agent mineral talc Mistron Vapor R from Mineral and Pigment Solution Southwest, heat stabilizer ( 1098) from BASF Corporation. Hostanox P-EPQ was purchased from Clariant Corporation. Unless otherwise stated, the additives (mineral talc Mistron Vapor R, 1098, and ) were used in the following amounts: 0.1 wt.%, 0.2 wt.%, and 0.8 wt.% respectively

[0103] Example 1 - Polybutylene terephthalate

[0104] This example demonstrates the mechanical and dielectric properties of a polyester composition containing PBT.

[0105] To demonstrate the mechanical and dielectric properties, several samples were prepared. Tables 1 to 3 provide the sample parameters for the examples (“E”) and comparative examples (“CE”). Table 1 shows the sample parameters and test results of polyester blends containing PBT, PMP, and a glass fiber mixture including low D k / D f glass fiber and high D k / D f E-glass fiber. Table 2 shows the sample parameters and test results of polyester blends containing PBT, PMP, and low D k / D f glass fiber as the sole glass fiber. Table 3 shows the sample parameters and test results of polyester blends containing PBT and PMP that do not contain glass fiber. In the table, “PE weight ratio” refers to the polyester weight ratio as defined above.

[0106] The impact properties were measured according to ASTM D256. Ten injection-molded ASTM flexural bars were measured. The tensile properties were measured according to ASTM D638. Five injection-molded ASTM tensile bars were measured, and the characterization was carried out at 2 mm / min for the entire test. The ASTM tensile bars had a length of 50.08 ± 1 mm, a width of 12.7 ± 0.2 mm, and a thickness of 3.2 ± 0.4 mm.

[0107] The dielectric properties were measured according to ASTM D150 (1 kHz and 1 MHz) or D2520 (1.77 GHz and 2.45 GHz). For the dielectric properties measured using ASTM D150, the measurements were carried out on a 4.0 mm flat disk with a diameter of 50.8 mm. The D k and D f measurements at 1 MHz and 1 kHz were carried out on an injection-molded disk with dimensions of 50.8 mm diameter by 4.0 mm thickness. Before testing according to ASTM D150, the samples were conditioned according to the ASTM D618 procedure. For the dielectric properties measured using ASTM D2520, the measurements were carried out on an ASTM flexural bar with the following dimensions: 3.2 mm × 12.7 mm × 125 mm. The D k and D f measurements at 1.77 GPa and 2.45 GHz were carried out on an injection-molded rectangular ASTM flexural bar. For ASTM D2520, the samples were tested in the molded condition.

[0108] As pointed out above, Tables 1 to 3 show the test results.

[0109] Table 1

[0110]

[0111]

[0112] Table 2

[0113]

[0114]

[0115] Table 3

[0116]

[0117]

[0118] Referring to Tables 1 to 3, the samples containing glass fiber have significantly different notched impact behavior with varying PE weight ratios compared to the samples without glass fiber. Figure 1 is a graph showing the normalized notched impact strength versus PE weight ratio. The solid line (Series A) with solid circles shows the normalized notched impact strength of the samples without glass fiber (Table 3). The dashed line (Series B) with open circles shows the normalized notched impact strength of the samples containing only low D k / D f glass fiber as glass fiber (Table 2). The dotted line (Series C) with closed triangles shows the normalized notched impact strength of the samples containing a mixture of low D k / D f and high D k / D f glass fiber mixture (Table 1). For clarity, the normalized values represent the values of each series (each table) divided by the highest value of each series. The comparison of Series B with Series A shows that the presence of glass fiber unexpectedly and qualitatively fundamentally changes the behavior of the notched impact properties of the polyester blend. For example, Series A shows distinct inflection points at approximately 70% and 97% PE weight ratios, which are either absent or significantly smaller in magnitude in Series B. Similar results are observed when comparing Series C with Series A. In addition, the comparison of Series C with Series B shows that the addition of low D k / D f and high D k / D f glass fiber further unexpectedly and qualitatively changes the behavior of the notched impact values with varying PE weight ratios. Further still, the comparison of E4 with CE3 shows that at 20 wt.% GF1, when the polyester composition contains a blend of PBT and PMP, both notched and unnotched impact resistance increase unexpectedly. In all cases, these examples (PE weight ratios between 70% and 95%) have an excellent balance of impact properties and dielectric properties.

[0119] Example 2 - Polyethylene naphthalate

[0120] This example demonstrates the mechanical and dielectric properties of polyester compositions containing PEN.

[0121] To demonstrate the mechanical and dielectric properties, several samples were prepared. The sample parameters are provided in Table 4.

[0122] Table 4

[0123]

[0124]

[0125] Referring to Table 4, the samples with 92.7% and 85.5% PE weight ratios unexpectedly have increased notched impact resistance compared to the samples with 100% and 0% PE weight ratios. All examples (PE weight ratios between 70% and 90%) have an excellent balance of impact and dielectric properties. Further, it should be noted that the unnotched impact of E8 is greater than that of CE1 and E9. Both E8 and E9 have desirable dielectric properties. For clarity, CE2 is replicated in Table 4 for easy comparison.

[0126] The above embodiments are intended to be illustrative rather than restrictive. Additional embodiments are within the inventive concept. Further, although the present invention has been described with reference to specific embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Any incorporation by reference of the above documents is limited such that no subject matter contrary to the explicit disclosure herein is incorporated.

Claims

1. A polyester composition, comprising: - a semi-aromatic semi-crystalline polyester; - comprising at least 80 mol% of repeating units (R PO ) having at least 4 carbons, said mol% being relative to the total number of repeating units in the polyolefin, said repeating unit (R PO ) being represented by the following formula: wherein R5 to R8 are independently selected from the group consisting of hydrogen and C1-C 10 alkyl groups; - glass fiber having a D of no greater than 5.5 measured at 1 MHz according to ASTM D150 k and a D of no greater than 0.002 f ; and - from 80% to 93% by weight of the polyester; wherein - The weight ratio of the polyester is given by the following formula: and -W PE and W PO are the weights of the semi-aromatic semi-crystalline polyester and the polyolefin in the polyester composition, respectively.

2. The polyester composition according to claim 1, wherein The semi-aromatic semi-crystalline polyester contains repeating units R represented by the following formula PE :[[]]END]] wherein T is a C1-C 18 alkyl and Ar is an aryl group.

3. The polyester composition according to claim 2, wherein, Repeating unit R PE Represented by any one of the following formulas: and wherein R1 to R4, at each position, are independently selected from the group consisting of hydrogen and C1-C 12 alkyl groups, and q, n, and m are independently selected integers from 1 to 12.

4. The polyester composition according to any one of claims 1 to 3, wherein, the semi-aromatic semi-crystalline polyester is selected from the group consisting of cyclohexylene dimethylene terephthalate ("PCT"), polyethylene terephthalate ("PET"), polybutylene terephthalate ("PBT"), polyethylene naphthalate ("PEN"), and polybutylene naphthalate ("PBN").

5. The polyester composition according to any one of claims 1 to 3, wherein R6 to R8 are hydrogen.

6. The polyester composition according to claim 3, wherein R3 is C3 to C 10 alkyl group.

7. The polyester composition according to any one of claims 1 to 3, wherein The polyolefin is selected from the group consisting of poly(4-methyl-1-pentene), poly(1-butene), poly(1-pentene), and poly(1-hexene).

8. The polyester composition according to claim 1, wherein The polyolefin comprises at least 80 mol% of repeating units (R PO ) that include at least 5 carbons.

9. The polyester composition according to any one of claims 1 to 3, wherein, The polyolefin is poly(4-methyl-1-pentene).

10. The polyester composition according to any one of claims 1 to 3, further comprising high D k / D f glass fiber; Among them, The high D k / D f The glass fiber has a D greater than 5.0 at 1 MHz k , and a D greater than 0.002 at 1 MHz f .

11. The polyester composition according to any one of claims 1 to 3, wherein, The polyester composition comprises a D of not greater than 3.5 measured at 1 kHz according to ASTM D150 k and a D of not greater than 0.003 f .

12. The polyester composition according to any one of claims 1 to 3, wherein, The polyester composition includes a D of not greater than 3.4 measured at 1 MHz according to ASTM D150 k and a D of not greater than 0.03 f .

13. The polyester composition according to any one of claims 1 to 3, wherein The polyester composition includes a notched impact strength of at least 80 J / m measured according to ASTM D256.

14. The polyester composition according to any one of claims 1 to 3, wherein The polyolefin contains at least 99.5 mol% of repeating units (R PO ), where mol% is relative to the total number of repeating units in the polyolefin.

15. A mobile electronic device component comprising the polyester composition according to any one of claims 1 to 14.

16. The mobile electronic device component according to claim 15, wherein, The mobile electronic device is selected from the group consisting of mobile phones, personal digital assistants ("PDAs"), laptop computers, tablet computers, wearable computing devices, cameras, portable audio players, portable radios, global positioning system receivers, and portable game consoles.

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